VKM Report 2018:08

Pest risk assessment of sibiricus and

Opinion of the Panel on Plant Health of the Norwegian Scientific Committee for Food and Environment

Report from the Norwegian Scientific Committee for Food and Environment (VKM) 2018:08 Pest risk assessment of Dendrolimus sibiricus and Dendrolimus superans

Opinion of the Panel on Plant Health of the Norwegian Scientific Committee for Food and Environment 19.04.2018

ISBN: 978-82-8259-305-2 ISSN: 2535-4019 The Norwegian Scientific Committee for Food and Environment (VKM) Po 4404 Nydalen N – 0403 Oslo Norway

Phone: +47 21 62 28 00 Email: [email protected] www.vkm.no www.english.vkm.no

Cover photo: John Ghent, Bugwood.org

Suggested citation: VKM, Trond Rafoss, Daniel Flø, Leif Sundheim, Micael Wendell, Guro Brodal, Åshild Ergon, Christer Magnusson, Arild Sletten, Halvor Solheim (2018). Pest risk assessment of Dendrolimus sibiricus and Dendrolimus superans. Opinion of the Panel on Plant Health of the Norwegian Scientific Committee for Food and Environment. VKM report 2018:08, ISBN: 978-82-8259-305-2, ISSN: 2535-4019. Norwegian Scientific Committee for Food and Environment (VKM), Oslo, Norway.

VKM Report 2018:08

Pest risk assessment of Dendrolimus sibiricus and Dendrolimus superans

Preparation of the opinion

The Norwegian Scientific Committee for Food and Environment (Vitenskapskomiteen for mat og miljø, VKM) appointed a project group to answer the request from the Norwegian Food Safety Authority. The project group consisted of two VKM members from the Panel on Plant Health and one two project managers from the VKM secretariat. Three external referees commented on and reviewed the manuscript. The VKM Panel on Plant Health evaluated and approved the final opinion drafted by the project group.

Authors of the opinion

Members of the project group that contributed to the drafting of the opinion (in alphabetical order after chair of the project group):

Trond Rafoss – Chair of the project group and chair of the VKM Panel on Plant Health. Affiliation: 1) VKM; 2) Norwegian Institute of Bioeconomy Research (NIBO)

Daniel Flø – Member of the project group and project manager in the VKM secretariat. Affiliation: VKM.

Leif Sundheim – Member of the project group and member of the VKM Panel on Plant Health. Affiliation: 1) VKM; 2) NIBO

Micael Wendell – Member of the project group and project manager in the VKM secretariat. Affiliation: VKM.

Members of the VKM Panel on Plant Health that contributed to the assessment and approval of the opinion:

In addition to Trond Rafoss and Leif Sundheim, these were (in alphabetical order)

Guro Brodal – Member of the VKM Panel on Plant Health. Affiliation: 1) VKM; 2) NIBO

Åshild Ergon – Member of the Panel Member of the VKM Panel on Plant Health. Affiliation: 1) VKM; 2) Norwegian University of Life Sciences (NMBU)

Christer Magtnusson – Member of the VKM Panel on Plant Health. Affiliation: 1) VKM; 2) NIBO

Arild Sletten – Member of the VKM Panel on Plant Health. Affiliation: 1) VKM; 2) NIBO

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Halvor Solheim – Member of the VKM Panel on Plant Health. Affiliation: 1) VKM; 2) NIBO

Acknowledgment

VKM would like to thank Salla Hannunen, Finnish Food Safety Authority (Evira), Michal Czyz, Institute of Plant Protection – National Research institute (Poland) and Jean-Claude Grégoire, Université Libre de Bruxelles (Belgium) and members of the EFSA Panel on Plant Health for reviewing the opinion and providing constructive criticism. VKM would also like to thank Oleg Kulinich and Yuri Baranchikov for providing expertise and insights relevant literature regarding biology and occurrence in .

Competence of VKM experts

Persons working for VKM, either as appointed members of the Committee or as external experts, do this by virtue of their scientific expertise, not as representatives for their employers or third party interests. The Civil Services Act instructions on legal competence apply for all work prepared by VKM.

VKM Report 2018:08

Table of Contents

Summary ...... 8 Sammendrag på norsk ...... 11 Abbreviations and/or glossary ...... 13 Background as provided by the Norwegian Food Safety Authority ...... 15 Terms of reference as provided by the Norwegian Food Safety Authority ...... 16 Assessment ...... 17 1 Introduction ...... 17 1.1 Purpose and scope ...... 17 1.2 Information collection ...... 17 Previous pest risk assessments ...... 17 List of conclusions from previous PRA’s: ...... 18 Literature search strategy ...... 19 Data collection ...... 19 1.3 Ratings of probabilities and uncertainties ...... 19 2 Pest identity, biology, occurrence, hosts and regulatory status ...... 20 2.1 Pest identification, name and taxonomic position ...... 20 Biological information ...... 20 2.1.1.1 Dendrolimus sibiricus ...... 20 2.1.1.2 Dendrolimus superans ...... 21 Taxonomic position ...... 21 Host plant species ...... 22 2.1.3.1 Dendrolimus sibiricus ...... 23 2.1.3.2 Dendrolimus superans ...... 23 Geographical distribution ...... 23 2.1.4.1 Dendrolimus sibiricus ...... 23 2.1.4.2 Dendrolimus superans ...... 26 2.1.4.3 Occurrence of the pests in the PRA area ...... 26 2.2 Regulatory status ...... 26 3 Assessment of the probability of introduction and spread ...... 28 3.1 Probability of entry of the pest ...... 28 Identification of pathways for entry ...... 28 3.1.1.1 Human mediated spread as an entry of the pest ...... 30

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Living trees ...... 30 Coniferous wood in the rough ...... 31 Foliage and branches ...... 33 3.1.1.2 Natural spread as an entry of the pest...... 34 Dendrolimus sibiricus ...... 34 Dendrolimus superans ...... 35 Probability of the pest being associated with the pathways ...... 36 Probability of survival during transport or storage ...... 36 Probability of the pest surviving existing pest management procedures ...... 37 Probability of transfer to a host ...... 37 Conclusions on the probability of entry ...... 37 3.2 Probability of establishment ...... 38 Climatic suitability ...... 38 Natural enemies ...... 41 Conclusion of the probability of establishment ...... 41 3.3 Probability of spread after establishment ...... 41 3.4 Endangered area within the PRA area ...... 42 3.5 Assessment of impact ...... 43 3.6 Conclusion of the impact ...... 44 4 Identification and evaluation of risk reduction options ...... 45 4.1 Risk reduction options to prevent entry and establishment ...... 45 4.2 Management options to prevent further spread ...... 47 4.3 Regulation of Dendrolimus sibiricus and D. superans ...... 47 Establishment of demarcated zones ...... 47 Pesticide application ...... 47 Imported host plants for planting and cut branches from the infested area should be free from soil ...... 48 Burn infested material ...... 48 Adhesive tape ...... 48 4.4 Evaluation of effectiveness and feasibility of risk reduction measures ...... 48 4.5 Regulation of Dendrolimus sibiricus and D. superans ...... 48 Demarcated zones ...... 48 Pesticide application ...... 49 Burning of infested material ...... 49 Adhesive tape on trees ...... 49

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4.6 Conclusion on the risk reduction measures to prevent entry and establishment ...... 50 5 Uncertainties ...... 51 6 Conclusions (with answers to the terms of reference) ...... 52 7 Data gaps ...... 59 8 References ...... 61 Appendices ...... 65 Appendix I ...... 65 Appendix II ...... 67

VKM Report 2018:08

Summary

The two lappet , Dendrolimus sibiricus and D. superans, are largely native to Russia and restricted parts of Northern China, , and Japan. The pests feed on several native conifer species (Pinaceae), including species found in Norway; Norway () and Scots (). In Russia, these moths can be major pests, where reoccurring defoliation of Coniferous trees under drought conditions eventually lead to death.

An article published in 2001 on D. sibircus, stated that the species had spread west to Moscow from its natural area of distribution east of the 60th . This article sparked an interest in the species and generated a concern that the species soon could reach with potentially devastating consequences for the conifer forests in Europe.

Historically, Russian scientists have considered D. superans as a single species with two subspecies; D. superans sibiricus and D. superans albolineatus. However, recent genetic analyses have indicated that they are two distinct species, D. sibiricus and D. superans.

The Norwegian Scientific Committee for Food and Environment (VKM) has been asked by the Norwegian Food Safety Authority (NFSA) to: 1) Summarize current knowledge about of D. sibiricus and D. superans and closely related lappet moths as background for identifying their current distribution areas. 2) Summarize current knowledge of spread of the species and their host plants, including natural spread. Is there a risk that D. sibiricus can be spread naturally from Russia to Norway? 3) List countries where the status of the pests should be considered as present. 4) Identify possible pathways for introduction of the two species into Norway. 5) Assess the probability of the pests entering Norway from countries listed in (3) through the pathways listed in (4). 6) Estimate the potential of establishment and further spread of the species in the Norwegian environment if they are introduced, also regarding climatic changes in the future. 7) Assess the potential consequences in Norway (environmental, economic and social effects) if they are introduced and established. VKM was asked to look at these effects in two scenarios: a) No regulations for these (no measures taken). b) The insects are regulated as quarantine pests with certain specific requirements. 8. Identify relevant risk reduction measures and evaluate their effectiveness

VKM Report 2018:08 8 and feasibility. For wood packing material, also consider if ISPM 15 is effective enough to prevent introduction of the pests.

VKM considers the probability of entry of D. sibiricus and D. superans by natural spread as unlikely and very unlikely, respectively mainly because of the geographical distance and partial sea barriers between Norway and the infested areas.

The overall probability of entry by human mediated pathways for D. superans and D. sibiricus is considered as unlikely with a medium level of uncertainty.

VKM is of the opinion that , should D. sibiricus enter the pest risk analysis (PRA) area, the probability of establishment and spread are considered as unlikely, due to the combination of suboptimal environmental conditions and the fact that the two potential host trees, Norway spruce (P. abies) and Scots pine (P. sylvestris), are intermediate and poor hosts, respectively.

The potential damage, if D. sibiricus should enter Norway, is considered low, again due to the combination of suboptimal environmental conditions and the fact that the two potential host trees, Norway spruce (P. abies) and Scots pine (P. sylvestris), are intermediate and poor hosts, respectively.

It is forbidden to import into Norway Coniferales of plants, wood with bark and chips of wood with bark, isolated bark and wood waste of Coniferales from Non-European countries and Portugal are prohibited according to “Regulations of 1 December 2000 no. 1333 relating to plants and measures against pests” (Ministry of Agriculture and Food, 2017).

Furthermore, VKM is of the opinion that the risk-reduction measures in the EPPO Commodity-specific phytosanitary measures PM 8/2 (2) Coniferae, can be considered satisfactory under Norwegian conditions.

Treatments of wood packing materials, which are regulated under ISPM 15, are regarded as effective measures to prevent introduction of the pests to the PRA-area.

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Key words: Pest Risk Analysis (PRA), pest risk assessment, distribution, spread, entry, establishment, management options, impact, economic and environmental consequences, VKM, Norwegian Scientific Committee for Food and Environment, Norwegian Food Safety Authority.

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Sammendrag på norsk

De to møll-artene Dendrolimus sibiricus og Dendrolimus superans, har sin naturlige utbredelse hovedsakelig i Russland, men de finnes også i avgrensede deler av nordlige Kina, Mongolia, Kasakhstan og Japan. Møllartene spiser nålene til en rekke bartrær (Coniferae), inkludert gran (Picea abies) og furu (Pinus sylvestris). Begge bartrærne er utbredt i Norge. I tørkeperioder kan de to møllartene gjøre stor skade på skog i Russland. Trær som har vært utsatt for tørke og som også blir utsatt for flerårige angrep av disse nålespisende insektene, kan dø. I Russland har D. superans vært ansett som en art, med to underarter; D. superans sibiricus og D. superans albolineatus, siden disse to er svært like. Nye genetiske analyser har vist at dette er to ulike arter som heter henholdsvis D. sibiricus og D. superans.

En Russisk artikkel som ble publisert i 2001 (Gninenko and Orlinskii, 2002), beskrev at D. sibiricus hadde spredt seg vestover fra sitt naturlige utbredelsesområde i Uralfjellene rundt den sekstiende breddegrad til Moskva. Artikkelen har skapt interesse for arten og bekymring for at den kan spre seg til Europa og kanskje gjøre stor skade på europeiske barskoger.

Mattilsynet har bedt Vitenskapskomiteen for mattrygghet (VKM) om å utføre en risikoanalyse i henhold til ISPM nr. 11 for Dendrolimus sibiricus og Dendrolimus superans i Norge, og om å spesifikt svare på følgende spørsmål: 1) Å gi en sammendrag på dagens kunnskap på taksonomi av D. sibiricus og D. superans samt nært beslektede arter som bakgrunn for å kartlegge dagens utbredelse. 2) Gi en sammendrag på dagens kunnskap angående utbredelse av artene og deres vertsplanter, inkludert naturlig spredning av D. sibiricus og om det er en risiko for at D. sibiricus kan spre seg naturlig fra Russland til Norge. 3) Gi en sammendrag på land hvor arten er etablert. 4) Oppsummer mulige smitteveier for introduksjon for de to artene til Norge. 5) Vurder sannsynligheten for at artene kan introduseres I Norge fra land som r identifisert I punkt tre, fra smitteveier oppsummert I punkt fire. 6) Estimer potensialet for etablering og videre spredning av de to artene i Norge om de blir introduserte Norge under dagens klima og framtidig klima scenario. 7) Vurder potensielle konsekvenser for Norge (Miljømessige, økonomiske og sosiale effekter) om artene etableres. Vurder to scenario: a) artene reguleres ikke (ingen tiltak iverksettes), eller B) artene reguleres som karanteneskadegjørere med påfølgende krav. 8) Oppsummer relevante risikoreduserende tiltak og evaluer effekten og gjennomførbarhet. Vurder også om

VKM Report 2018:08 11 den Internasjonal standard for treemballasje ISPM nr. 15 er tilstrekkelig for forhindre introduksjon av artene.

VKM mener at sannsynligheten for at D. sibiricus og D. superans sprer seg naturlig til Norge er lav. Årsaken er at det er lang avstand mellom Norge og områdene hvor disse artene forekommer i dag, og at insektene må krysse hav eller passere rundt Bottenviken. VKM mener at det er lav sannsynlighet for at de to Dendrolimus-artene kan introduseres via handelsvarer som inneholder bartrær, «planter og plantemateriale» og «tømmer», og kategorien «Lauvverk, blad, greiner og andre plantedeler».

VKM mener at det er lav sannsynlighet for etablering og spredning av D. sibiricus i Norge. Årsaken er kombinasjonen av sub-optimale klimatiske forhold og at de to vertstrærne gran (P. abies) og furu (P. sylvestris) er ansett for å være henholdsvis medium og dårlige vertstrær. Skadepotensialet regnes også av den grunn som lite.

VKM mener at det norske importforbudet, fra ikke-europeiske land og Portugal, som gjelder planter og plantedeler, tre med bark og flis av tømmer med bark, isolert bark og treavfall fra bartrær slikt beskrevet i vedlegg 3 av forskrift om planter og tiltak mot planteskadegjørere (FOR-200-12-01-1333) (Ministry of Agriculture and Food, 2017) er effektive. VKM mener i tillegg at risikoreduserende tiltak beskrevet i EPPO`s «Commodity-specific phytosanitary measures PM 8/2 (2) Coniferae» kan regnes som effektive under norske forhold.

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Abbreviations and/or glossary

Table 1. Definition and explanation of terms used in the assessment. The current opinion is mainly according to the ISPM No.5 Glossary of phytosanitary terms by FAO (2015). Definition and explanation of term CABI Centre for Agriculture and Biosciences International Commodity A type of plant, plant product, or other article being moved for trade or other purpose EFSA European Food Safety Authority Endangered area An area where ecological factors favour the establishment of a pest whose presence in the area will result in economically important loss Entry Movement of a pest into an area where it is not yet present, or present but not widely distributed EPPO European Plant Protection Organization EPPO PQR EPPO Plant Quarantine Data Retrieval system Establishment Perpetuation, for the foreseeable future, of a pest within an area after entry FAO Food and Agricultural Organization Introduction The entry of a pest resulting in its establishment Non-squared wood and Wood that retains some natural rounded surface. Bark may remain on bark the wood NFSA The Norwegian Food Safety Authority NIBIO Norwegian Institute of Bioeconomy Research Other non-squared Logs with bark, debarked logs, fire wood, sawn wood containing some wood and bark natural rounded surface, isolated bark Pathway Any means that allows the entry or spread of a pest Pest Any species, strain or biotype of plant, or pathogenic agent injurious to plants or plant products Plants for planting Plants intended to remain planted, to be planted or replanted PRA Pest Risk Analysis PRA area Area in relation to which a pest risk analysis is conducted Round wood Wood not sawn longitudinally, carrying its natural rounded surface, with or without bark Sawn wood Wood sawn longitudinally, with or without its natural rounded surface, with or without bark

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Definition and explanation of term Spread Expansion of the geographical distribution of a pest within an area Squared Wood Wood from which all natural rounded surface has been removed: no wane, no bark Tariff codes Customs codes according to the World Customs Organization’s internationally agreed Harmonized System. VKM The Norwegian Scientific Committee for Food and Environment Wood packaging Wood or wood products (excluding paper products) used in material supporting, protecting or carrying a commodity (includes dunnage)

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Background as provided by the Norwegian Food Safety Authority

The two lappet moths, Dendrolimus sibiricus and Dendrolimus superans, which are closely related to the pine-tree lappet (), have the potential to damage a wide range of different conifers. During a period of 25 years (1932-1957) D. sibiricus damaged 7 million ha of forest in West Siberia and Chita Oblast (EPPO, 2005). The two species naturally occur in , and D. sibiricus is known to have spread into the European parts of Russia. Neither of the two species are known to be present in Norway. However, it is suggested that the moths can enter with a presumed pathway by wood and wood products. Lappet moths are generally good flyers, and both these Dendrolimus species may naturally spread by a rate of 100 km per year (EPPO, 2005).

EPPO conducted a Pest Risk Assessment for D. sibiricus in 2000 (EPPO, 2000a) and for D. superans in 2003 (EPPO, 2003). However, there has been no complete Pest Risk Analysis, including both a Pest Risk Assessment and a Pest Risk Management, for any of the two Dendrolimus species.

Both species are listed on the «EPPO A2 list». Furthermore, D. sibiricus is on the EU list of «Pest forbidden to introduce or spread».

Today, the two Dendrolimus species are not regulated as quarantine pests for Norway.

Considering the supposed damage potential for the Norwegian conifer forests, the Norwegian Food Safety Authority (NFSA) asked the Norwegian Scientific Committee for Food and Environment (VKM) to carry out an assessment of the potential for entry, establishment and damage of the two plant pests D. sibiricus and D. superans in Norway. The NFSA will use the VKM risk assessment as a basis to determine whether D. sibiricus and D. superans should be regulated as quarantine plant pests for Norway and if specific phytosanitary actions should be taken to prevent their introduction.

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Terms of reference as provided by the Norwegian Food Safety Authority

VKM is requested to carry out a pest risk analysis according to ISPM 11 for Dendrolimus sibiricus and Dendrolimus superans in Norway, including special information on:

1. Summarize current knowledge about the taxonomy of D. sibiricus and D. superans and closely allied lappet moths as background for identifying their current distribution areas.

2. Summarize current knowledge about spread of the species and their host plants, including natural spread. Is there a risk that D. sibiricus can be spread naturally from Russia to Norway?

3. List countries where the status of the pests should be considered as present.

4. Identify possible pathways for introduction of the two species into Norway.

5. Assess the probability of the pests entering Norway from countries listed in (3) through the pathways listed in (4.).

6. Estimate the potential for establishment and further spread of the species in the Norwegian environment if they are introduced, also regarding climatic change in the future.

7. Assess the potential consequences for Norway (environmental, economic and social effects) if they are introduced and established. We would like you to look at these effects in two scenarios: a) No regulations for these insects (no measures taken). b) The insects are regulated as quarantine pests with certain specific requirements.

8. Identify relevant risk reduction measures and evaluate their effectiveness and feasibility. For wood packing material, also consider if ISPM 15 is effective enough to prevent introduction of the pests.

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Assessment

1 Introduction

1.1 Purpose and scope

This document presents a scientific opinion prepared by the VKM Panel on Plant Health (hereafter referred to as the Panel), in response to a request from the Norwegian Food Safety Authority. The opinion is a risk assessment of the two closely related lappet moths D. sibiricus and D. superans for Norway. Furthermore, the opinion identifies and evaluates risk reduction options in terms of their effectiveness in reducing the plant health risk posed by these moths.

The PRA (Pest Risk Analysis) area of this risk assessment is Norway.

1.2 Information collection

Previous pest risk assessments

The previous pest risk assessments of D. sibircus and D. superans are listed below:

EPPO (1998). Pest risk analysis to decide immediate action to be taken on interception of a pest in an EPPO country: Dendrolimus sibiricus.

EPPO (2000a). Pest risk assessment scheme (00/8481): Dendrolimus sibiricus Tschetverikov (: ): 16.

EPPO (2000b). Report of a Pest Risk Assessment: Dendrolimus sibiricus: 3.

EPPO (2003). Report of a Pest Risk Management: Dendrolimus superans (05-11895): 3.

Kubasik et al. (2017) Analizy Zagrożenia Agrofagiem (Ekspres PRA) dla Dendrolimus sibiricus, Rzeczpospolita Polska, Institute of Plant Protection-NRI Poznan, Poland

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List of conclusions from previous PRA’s:

EPPO (1998) concluded that D. sibiricus threatens large areas of conifer forests in Europe, with the potential to cause serious and destructive epidemics in European conifer forests.

EPPO (2000a) concluded that the entry of the D. sibiricus into the EPPO region is more likely to occur by natural spread and import of untreated wood with bark, dunnage or packing material, and less likely to occur by import of host plants for planting and cut branches. It was also concluded that the probability of establishment was considered to be high in the EPPO region, including Norway. The potential impact within the EPPO region was also considered to be high, including both the direct damage to coniferous plantations and forests (mainly Abies spp., Pinus spp., Larix spp., and Picea spp.) resulting in wood losses, environmental damage to natural forests, including deforestation over large areas, and social damage to people living in damaged areas.

EPPO (2003) concluded that the main pathways for D. superans are, in order of descending importance: 1) Plants for planting of host trees that may carry eggs, larvae and cocoons of the pest on bark and branches. Management options: Plants free from soil, visual inspection, harvesting in restricted periods, pest free areas and protected areas. 2) Cut branches (including Christmas trees) that may carry eggs, larvae and cocoons of the pest. Management options: Fumigation, visual inspection, harvesting in restricted periods, and pest free areas. 3) Wood with bark of host plants that may carry eggs and larvae of the pest. 4) Isolated bark of host plants that may carry eggs and larvae of the pest. 5) Natural spread has been identified as a pathway, but the EPPO Panel did not consider this possibility because of the long distance between the actual area of distribution of the pest and the endangered area.

Kubasik et al. (2017) concluded that D. sibiricus poses a potentially very high threat to the forests of Poland, because the high proportion of coniferous trees, and that suitable climatic conditions facilitate establishment of this species, if it enters into Poland. However, due to low imports of relevant conifer commodities to Poland, the probability of introduction was considered low.

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Literature search strategy

This section describes the literature search conducted for retrieving the scientific documentation available for this opinion.

A literature search was conducted in September 2017 and was last updated in March 2018. with the species names “Dendrolimus sibiricus” and “Dendrolimus superans” with default settings, in JSTOR (2017), ScienceDirect (2017), Springer Link (2017) and Web of Knowledge (2017). The reference lists in identified publications were screened for additional relevant publications. Publications of all ages in English were included.

If additional relevant references were discovered (e.g. in publication reference lists), these were included. Additional literature was also retrieved by the members of the project group, due to their expertise on the subject. Furthermore, literature was also obtained from collaboration with the Russian scientists Oleg Kulinich and Yuri Baranchikov.

Data collection

Data on import statistics for relevant commodities into Norway were downloaded from Statistics Norway (SSB, 2017), using StatBank Open data API (Application Programming Interface) in R (R Core Team, 2017) using the packages httr (Wickham, 2017) and rjstat (Schumacher and Malmedal, 2016).

Data for import of relevant commodities into Sweden and Finland were manually downloaded from the Eurostat (2017) CN8 database.

1.3 Ratings of probabilities and uncertainties

The conclusions for probability of entry and establishment of the pests are presented and rated separately, following a fixed scale: Very unlikely, unlikely, moderately likely, likely, very likely. The descriptors for these qualitative ratings are shown in Appendix 2

For the conclusions on entry and establishment, the levels of uncertainty are rated separately, following a fixed scale: Low, medium, high. The descriptors for these qualitative ratings of uncertainty are presented in Appendix 2

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2 Pest identity, biology, occurrence, hosts and regulatory status

2.1 Pest identification, name and taxonomic position

Dendrolimus sibiricus is the most destructive pest of conifers in Russia. In the period between 1994 and 1996, D. sibiricus damaged 700.000 ha of forest in Krasnoyarsk krai (Zhirin et al., 2016), between 1954 and 1957 the pest killed over 1.5 million ha of pine near the Ket- and Chulym rivers (Kharuk et al., 2016), and between 1932 and 1957, the pest damaged 7 million hectares of forest and killed 50% of the trees in western Siberia and in the Chita Oblast (Baranchikov and Montgomery, 2014). Dendrolimus sibiricus inhabits an area stretching from the Pacific Ocean across Russia past the Ural Mountains (Figure 1). However, there are ambiguities in the historic records of the distribution of these pests. The exact geographical distribution remains obscure, as the alleged expansion westwards towards Moscow (Gninenko and Orlinskii, 2002) has been questioned (Mikkola and Stahls, 2008), and thought to be based on a misidentification of D. pini as D. sibiricus (Baranchikov et al., 2006).

The closely related D. superans is restricted to the Sakhalin and the Kurile Islands, Sakhalin Oblast Russia, and northern Japan (EPPO, 2005). Dendrolimus superans is reported not to extend its range or attacking European conifer species. However, little information is available in English on this species.

Biological information

The biology of D. sibiricus and D. superans is very similar and described in detail by (EPPO, 2005).

2.1.1.1 Dendrolimus sibiricus

In Russia, D. sibiricus can attack a wide range of host species (as described in chapter 2.1.3). Adults fly from the end of June to the beginning of August, and each female can lay

VKM Report 2018:08 20 up to 800 eggs (EPPO, 2005). Eggs (1.9-2.2 mm in length) are laid on the bark of stems, needles or branches of host trees, where larvae (length 60-82 mm) hatch after 13 to 22 days and start feeding on the needles. Afterwards, larvae that have overwintered make cocoons in June to late July and pupate (pupae 50-110 mm in length) in the trees. The life cycle typically takes from one to two years depending on population density and temperature. Larvae can have between six and eight instars, and diapausing larvae overwinter once or twice in the ground, in litter or underneath moss. However, parts of the population (larvae) can enter summer diapause (a period of slow development of the third- to fifth-instar larvae), if food availability is low or abiotic conditions are unfavourable, prolonging their life cycle up to four years (Kirichenko et al., 2011). Due to this prolonged diapause, parts of the population can have a life cycle of either two, three or four years, which contributes to the population persistence during unfavourable conditions.

2.1.1.2 Dendrolimus superans

Dendrolimus superans can attack a wide range of host species (EPPO, 2005). Typically, its life cycle takes one to two years, depending on food availability and temperature. Dendrolimus superans is active in the period from June to August, and prefers forests older than 50 years (EPPO, 2005).

Taxonomic position

Both D. sibiricus and D. superans are , and the taxonomic positions of the pests are presented in Table 2. Historically, many researchers have considered D. superans to be a single species with two subspecies; D. superans sibiricus Tschetverikov and D. superans albolineatus Butler (Kononov et al., 2016). Both of these species are closely related to the pine-tree lappet moth (Dendrolimus pini) which is present in Norway and the rest of Europe. According to Kononov et al. (2016) there are about 30 species in the genus Dendrolimus, but only eight species in Eurasia, most of which are native to Far East Asia.

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Table 2. Taxonomic position of the pests.

Dendrolimus sibiricus Dendrolimus superans

Name Dendrolimus sibiricus Dendrolimus superans (Butler, 1877) (Chetverikov, 1908)

Synonyms Dendrolimus superans sibiricus Dendrolimus superans albolineatus (Chetverikov, 1908) (Butler, 1877)

Dendrolimus laricis (Chetverikov, Dendrolimus albolineatus (Matsumura, 1903) 1921)

Dendrolimus yezoensis (Matsumura)

Odonestis superans (Butler, 1877) Common name in Siberian silk moth Sakhalin silk moth English and caterpillar Russian Siberian conifer silk moth Sibirskiy shelkopryad The pest is an Class: Insecta, Class: Insecta, Order: Lepidoptera, Order: Lepidoptera,

Family: Lasiocampidae, Family: Lasiocampidae,

Genus: Dendrolimus, Genus: Dendrolimus,

Species: D. sibiricus Species: D. superans

Host plant species

The larvae of species in the genus Dendrolimus only infest conifer trees. Hardin and Suazo (2012) presents an extensive list of reported hosts plant species for D. sibiricus and D. superans. Several of the host plant species presented by Hardin and Suazo (2012) can be found as ornamental landscape trees in Norway. However, since these host trees are sparsely used and rarely planted in small forest patches, the Panel do not consider these host plants of interest for further investigation within this PRA.

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2.1.3.1 Dendrolimus sibiricus

The main hosts for D. sibiricus are the Siberian larch (Larix sibirica), Siberian pine (Pinus sibirica), Siberian fir (Abies sibirica), and Siberian spruce (Picea obovata). However, the pest is reported to damage more than 20 different species of Pinaceae (EPPO, 2005).

Two potential hosts are present in Norway, the Norway spruce (Picea abies) and the Scots pine (Pinus sylvestris). Kirichenko et al. (2009) showed, in a larval host plant bioassay- experiment with European tree species, that Picea abies and Pinus sylvestris were intermediate and poor hosts, respectively, for D. sibiricus larvae. However, P. abies was preferred over P. sylvestris. For larvae feeding on P. sylvestris and P. abies, the developmental time increased, and larvae mortality reached 66.7% and 14.5%, respectively, compared to 3.2% mortality for the larvae fed on Larix decudia, which provided the lowest larvae mortality in the same period. Kirichenko et al. (2009) concluded that D. sibiricus will be able to develop on the main European conifer hosts mentioned above, resulting in severe damage to large forest areas.

2.1.3.2 Dendrolimus superans

The main hosts for D. superans are Larix kamtschatica, Pinus pumila, Picea ajanensis and Abies sachalinensis (EPPO, 2005), all of which are absent from Norway –or only used sparsely as landscape trees-, and they are mostly growing in the far eastern federal districts of Russia. According to EPPO (2005) there are no specific reports concerning the suitability of European conifers as hosts for D. superans. To the knowledge of the Panel, there are no data indicating that any Norwegian tree species is a suitable host of D. superans. On the other hand, there are no data showing that Norwegian tree species cannot be suitable hosts of D. superans.

Geographical distribution

2.1.4.1 Dendrolimus sibiricus

Dendrolimus sibiricus is native to Russia, and restricted parts of northern Kazakhstan, Mongolia and China (EPPO, 2005).

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Dendrolimus sibiricus is present west of the 60th meridian east in European Russia (Figure 1). However, the exact western border of the geographical distribution of D. sibiricus, is disputed among experts (Gninenko and Orlinskii, 2002; Kirichenko et al., 2009; Kononov et al., 2016). The geographical distribution of the species are presented in figure 1 and 2.

Also, the northern limit of D. sibirucus is uncertain, but according to (Rozhkov, 1963) (printed in EPPO, 2005), the city of Yakutsk is the northernmost record of the species (Figure 2). However, this area is sparsely populated, and there are uncertainties as to which data Rozhkov (1963) used to draw his map. Therefore, D. sibiricus could be more widespread in Northern Russia than previously reported (Flament et al., 2017). Also, there are uncertainties as to the southern limits of the distribution of the pest in China, Mongolia and Kazakhstan. Therefore, the distribution of the main hosts may be the best indicator of the historic distribution of D. sibiricus, even though the northern limits in this case could be overestimated.

Figure 1. Map of Russia showing the federal subjects, where Dendrolimus sibiricus is present (dark gray areas) and not present (light gray areas). The distribution of D. sibiricus is uncertain for some of the federal subjects in European Russia (gray areas). The black lines represent the distribution for some of the main host species for D. sibiricus. The 60th meridian east represents the border between Europe and Asia. The map was compiled from literature and personal communication, see appendix I for full references. Data on the distribution of Picea obovata were unavailable.

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Figure 2. Map of the geographical distribution of Dendrolimus sibiricus by Rozhkov (1963), Reprinted from EPPO Bulletin Volume 35, Issue 3, pages 390-395 (EPPO, 2005)

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2.1.4.2 Dendrolimus superans

Dendrolimus superans is native to Japan, China and Far East Russia (Primorsky krai, Sakhalin- and Kurile Islands, Sakhalin Oblast) (Figure 3).

Figure 3. Map of Russia showing the federal subjects, where Dendrolimus superans is present (black areas) and not present (gray areas) (EPPO, 2005; Kononov et al., 2016).

2.1.4.3 Occurrence of the pests in the PRA area

The pests are not present in the PRA area.

2.2 Regulatory status

Dendrolimus sibiricus and D. superans are currently not regulated in the PRA-area. However, D. sibiricus and D. superans are on the «EPPO A2 List of pests recommended for regulation as quarantine pests» (Table 3). Dendrolimus sibiricus is also included in the EU Plant Health Legislation by EU Directive 2000/29 Annex I/AI, requiring a phytosanitary certificate issued by Russia, ensuring that plants and plant products are inspected and free from D. sibiricus (Council Directive 2000/29/EC, 2000 ). See Table 3 for further information regarding regulation

VKM Report 2018:08 26 of D. sibiricus and D. superans. Furthermore, it is forbidden to import into Norway Coniferales of plants, wood with bark and chips of wood with bark, isolated bark and wood waste of Coniferales from Non-European countries and Portugal are prohibited according to“Regulations of 1 December 2000 no. 1333 relating to plants and measures against pests” (Ministry of Agriculture and Food, 2017).

Table 3. Regulatory status of Dendrolimus sibiricus and D. superans. EAEU – Eurasian Economic Union, EU – European Union, EPPO – European and Mediterranean Plant Protection Organization. Species Country/Organization List category Year regulated EPPO A2 List 2002 EU Annex I/AI/A1 List 2009

EAEU A2 list 2016 Ukraine A1 list 2010 Dendrolimus sibiricus Turkey A1 list 2007

Russia A2 list 2014 Kazakhstan A1 list 2009 EPPO A2 List 2005

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3 Assessment of the probability of introduction and spread

Dendrolimus sibiricus has never been intercepted outside its main area of distribution, and in Russia there is no, or very slow spread westwards. In addition, there are currently no imports of commodities that would support entry to the PRA-area. To the best of the Panels knowledge D. superans has never been intercepted outside its main area of distribution, and in Russia there is no report of a westward spread. Furthermore, it is forbidden to import into Norway Coniferales of plants, wood with bark and chips of wood with bark, isolated bark and wood waste of Coniferales from Non-European countries and Portugal are prohibited according to “Regulations of 1 December 2000 no. 1333 relating to plants and measures against pests” (Ministry of Agriculture and Food, 2017).

3.1 Probability of entry of the pest

The special event, when a species crosses a country border, is in a PRA context classified as an “entry” event, while further spread inside the actual country or administrative unit, is denominated as spread (see glossary).

Identification of pathways for entry

The pathways are separated into natural spread and human mediated spread as pathways for entry. Three human mediated pathways are considered as possible entries of the D. sibiricus and D. superans into Norway; Living trees, coniferous wood in the rough and import of foliage and branches (Table 4).

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Table 4. List of human mediated pathways of entry of Dendrolimus sibiricus and D. superans into Norway (SSB 2017). Possible Tariff Short description Pathway Pest already Pathways codes regulated in intercepted on Norway? the pathway? (Yes/No) (Yes/No) Living trees 06.02 There has been no import Yes, from countries No imported from to Norway from Russia, outside Europe, as countries where Kazakhstan, China, well as Portugal. D. sibirucus and Democratic People's D. superans are Republic of Korea, From the European present Republic of Korea, part of Russia Mongolia or Japan during import of plants the past 20 years. needs a phytosanitary document. Import of 06.04 There has been no import Yes, from countries No branches and to Norway from Russia, outside Europe, as foliage. Kazakhstan, China, well as Portugal. Democratic People's Republic of Korea, From the European Republic of Korea, part of Russia Mongolia or Japan during import of plants the past 20 years. needs a phytosanitary document. Coniferous wood 44.03 There have been Yes, from countries No in the rough substantial imports of the outside Europe, as category “Coniferous wood well as Portugal. in the rough” from Russia to Norway during the past From the European 30 years, but these part of Russia imports have declined import of plants since 2000. needs a phytosanitary document.

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3.1.1.1 Human mediated spread as an entry of the pest

Living trees

The probability of entry of D. sibiricus and D. superans to Norway is considered as unlikely with a medium level of uncertainty.

During the past 30 years, there has been no import of living trees of Larix spp., Abies spp., Pinus spp. or Picea spp. from Russia to Norway. However, during the past 20 years there have been small numbers of living plants (unknown species) shipped to Norway from China (trade codes 06.02.90 Live plants and 06.02.99 Live plants) shown in Figure 3. There have been no other imports of living plants from countries where D. sibiricus is present. Furthermore, since 2001 it is forbidden to import into Norway Coniferales of plants, wood with bark and chips of wood with bark, isolated bark and wood waste of Coniferales from Non-European countries and Portugal are prohibited according to “Regulations of 1 December 2000 no. 1333 relating to plants and measures against pests” (Ministry of Agriculture and Food, 2017).

There has not been any import of living trees from Russia to Sweden, and only 12.4 metric tons of trees have been exported from Russia to Finland (Eurostat, 2017).

Figure 3. Amounts (metric tons) of Live plants (06.02) imported during the past 30 years from China. Data from Statistics Norway (SSB, 2017)

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Coniferous wood in the rough

The probability of entry of D. sibiricus and D. superans to Norway is considered as unlikely with a medium level of uncertainty.

There have been substantial imports of the category “Coniferous wood in the rough” (trade code 44.03) from Russia to Norway during the past 30 years, but these imports have declined since 2000 and from 2016 there has been no import (Figure 4). All of these products, if containing bark, could contain eggs, larvae and imago. The category with the highest volume, "Wood for pulping of spruce or other coniferous species" (trade code 44.03.2006) sums up to 1.508.417 metric tons over 16 out of 20 years and peaked in 1999 (Figure 4). The next category, "Coniferous sawn wood" (trade code 44.03.2001) sums up to 1.136.599 metric tons over 16 out of 20 years and peaked in 2000. Category "Wood for pulping" (trade code 44.03.2009) sums up to 127.687 metric tons over 12 out of 20 years and peaked in 2000, and "Wood for pulping of pine" (trade code 44.03.2005) sums up to 80.068 metric tons over 12 out of 20 years and peaked in 1994 (Figure 4). There were only 0.67 metric tons of "Coniferous Sawn wood" (trade code 44.03.2001) imported from Japan to Norway in 1992 (not shown in Figure).

Some of the sub-categories (of trade code 44.03) may contain Larix spp., Abies spp., Pinus spp. or Picea spp., although the custom statistics do not reveal the proportional content of the respective species. Furthermore, the Custom statistics do not reveal the origin of the respective commodities within Russia.

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Figure 4. Amounts (metric tons) of coniferous wood and wood products in the rough (trade code 44.03) imported during the past 30 years from Russia. Data from Statistics Norway (SSB, 2017).

Trade in conifer products with bark from European Russia is not regulated in the same way as trade from countries outside of Europe. This is of concern, since European Russia includes several climate types and ecoregions, potentially harbouring a number of unwanted species. Especially, the import of coniferous wood with bark originating from the east of the Ural Mountains (approximately 60th meridian east), represents a considerable risk for the entry of alien Dendrolimus species.

Generally, the imports of relevant commodities have shown high variability in the past. The volume of a commodity has, in some cases, changed more than 100% from one year to the next (Økland et al., 2012). This large temporal variation in imports from Russia has also been observed in other European countries, where timber imports from Russia had a dramatic increase in the 1990s, but since the turn of the century imports changed quickly in time and in area of origin (Piel et al., 2008). The decline and cessation of timber imports from Russia during the last decade may reflect a declining paper and pulp industry in Norway. Even though this trend indicates a cessation in import along relevant pathways, attention should be focused on further development of the import by monitoring import statistics.

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Foliage and branches

The probability of entry of D. sibiricus and D. superans to Norway is considered as unlikely with a high level of uncertainty.

It is uncertain which of the commodities under the heading Foliage, branches and other parts of plants (trade code 0604) include coniferous products. This commodity code may include coniferous wood with bark and other coniferous items that can host D. sibiricus. However, there was only a small volume of foliage, branches and other parts of plants (<0.5 metric ton) of “Subgroup off: 060491 Foliage, branches and other parts of plants” entering the PRA-area from Russia in 1998 (Figure 5).

Figure 5. Amounts (metric tons) of foliage, branches and other parts of plants (06.04) imported during the past 30 years from China, Japan, Russia and South Korea. Data from Statistics Norway (SSB, 2017).

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3.1.1.2 Natural spread as an entry of the pest.

Dendrolimus sibiricus

The probability of natural spread as an entry is considered as unlikely with a medium level of uncertainty.

The panel assesses that D. sibiricus cannot be expected to spread naturally from its current Western distribution limit in Russia (Figure 1) to Norway within the next couple of decades. In a worst case scenario, where D. sibiricus spreads westwards from Moscow at a rate of 50 km per year (EPPO, 2005), it would take more than 30 years for the species to reach Norway. In a situation of natural spread of D. sibiricus from the Moscow region to Norway the insects would probably need to fly north of the Gulf of Bothnia.

Based on the current data, it is difficult to conclude, with very high certainty, that there is no westward movement of the species. However, historical observations indicate that the westward spread may be very slow or non-existent. Dendrolimus sibiricus has probably been present in the Urals since the late 19th century or early 20th century without expanding westwards (Mikkola and Stahls, 2008 and references therein). Petersen W (1909) judged the western limit of distribution of D. sibiricus to be at the 59th meridian east, while Mikkola and Stahls (2008) and Eversmann (1844) reported it to be at the 56th and 58th meridian east, respectively. According to Gninenko and Orlinskii (2002) D. sibiricus is found in an area around the 52th meridian east, in the regions of Perm and Udmurtiya. Also, Rozhkov (1963) and Koltunov EV et al. (1997) judged the western limits of D. sibiricus to be at approximately at the 52th meridian east. However, Okunev PP (1955) reported D. sibiricus as far west as the 38th meridian east.

In 2001 a few specimens of D. sibiricus were reported as pheromone-trapped close to Moscow (Gninenko Y.U and Kryukov V.Y.U, 2007). Baranchikov et al. (2006) rejected this observation and considered it as a possible misidentification of D. pini as D. sibiricus. Dendrolimus sibiricus has not been recaptured in the Moscow, approximately 37th meridian east, or west of Moscow since 2001.

The trappings of these alleged D. sibiricus specimens close to Moscow back in 2001, triggered new studies and risk analyses predicting the risk of this species, e.g. to European forests (EPPO, 2005), to Finland by Möykkynen and Pukkala (2014) and to Poland (Kubasik et al., 2017). The Panel consider these studies as important precautionary reactions to what

VKM Report 2018:08 34 possibly could be signals of rapid spread. On the other hand, the Panel is of the opinion that such findings could also be a case of temporary presence, or spread, of the species. If subsequent surveillance shows that the species either is not causing any damage, or the surveillance does not recapture the species, indicating that the species has not been able to persist, the risk assessment should be updated and balanced with these results. In case it is suspected that the finding is due to an event of misclassification or otherwise cannot be confirmed, the studies and the risk assessments, which have been based on such data, should be revised.

The estimated westward spread of 50 km/year, reported by EPPO (2005) and by (Möykkynen and Pukkala, 2014), was probably based on the assumption that D. sibiricus was present in the Moscow area, which is not considered as a valid basis for the present assessment. There were no citations or calculations given for the statement of 50 km/year spread by EPPO (2005) or by Möykkynen and Pukkala (2014).

In addition, Baranchikov et al. (2006) maintained that D. sibiricus is not present in the Republic of Mari El. However, according to Oleg A. Kulinich (personal commutation), Russian NPPO registered D. sibiricus in the Republic of Mari El (approximately 47th meridian), Republic of Chuvash (approximately 46th meridian) and Kirov region (approximately 50th meridian) in 2016 (Figure 1, blue regions).

In agreement with Mikkola and Stahls (2008) and Baranchikov et al. (2006), the conclusion is that the westward spread of D. sibiricus is very slow or non-existent.

Dendrolimus superans

The probability of natural spread as an entry is considered as very unlikely with a low level of uncertainty.

To the best of the Panels knowledge D. superans has never been intercepted outside its natural habitat in the Far East Russia, Japan and Northern China. The moth is not expected to spread naturally from its current area of distribution in the Sakhalin- and Kurile Island (Sakhalin Oblast) in Russia, and from Hokkaido and the North of Honshu in Japan, to Norway.

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Probability of the pest being associated with the pathways

The overall probability of the pest being associated with the pathways are considered as very likely with high uncertainty.

Regarding the commodity “Wood in the rough”, it is probable that under non-outbreak conditions the pest occurrence has a low density throughout the area of distribution during the summer. Therefore, during logging, it is impossible to distinguish between trees infested with D. sibiricus larvae and trees not infested by D. sibiricus larvae. However, imago, larvae and cocoons will not be present when logging during the winter. This since, overwintering larvae hibernate in the ground, in the soil or under litter.

Regarding the commodity living trees and foliage and branches, one may make the same assumption that the pest occurrence may be at a low density throughout the area of distribution during the summer. In addition, the pest could be present in the soil during the winter in immediate proximity to the trees, i.e. nursery pots.

Probability of survival during transport or storage The overall probability of the pest to survive during transport and storage are considered as moderately likely with a high uncertainty.

The Panel considers that for the commodity "Wood in the rough”, eggs, larvae, cocoons and imago would be vulnerable to physical stress and other external forces and environmental stresses during transport and storage. Because eggs, larvae, cocoons as well as imago live on needles and branches of the trees, these stages may easily be crushed during transport and storage. Furthermore, the commodity “Wood in the rough” are cut trees without any needles and branches and, therefore, might be less suitable for survival of the larvae and imago.

The Panel concludes that the highest probability of survival of Dendrolimus spp. exists in the commodities “Living trees” and “Foliage, branches and other parts of plants”, because they may be handled more carefully and are transported in protected consignments.

To the knowledge of the Panel, there are no commercial procedures applied to any of the above-mentioned commodities that would decrease the probability of survival during transport or storage, if phytosanitary measures are not applied.

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Probability of the pest surviving existing pest management procedures

The overall probability of the pest to survive existing pest management procedures are estimated to be unlikely with medium uncertaincy.

It is forbidden to import into Norway Coniferales of plants, wood with bark and chips of wood with bark, isolated bark and wood waste of Coniferales from Non-European countries and Portugal are prohibited according to “Regulations of 1 December 2000 no. 1333 relating to plants and measures against pests” (Ministry of Agriculture and Food, 2017). Furthermore, D. sibiricus is also included in the EU Plant Health Legislation by EU Directive 2000/29 Annex I/AI, requiring a phytosanitary certificate issued by Russia, ensuring that plants and plant products are inspected and free from D. sibiricus (Council Directive 2000/29/EC, 2000 ).

Probability of transfer to a host

The probability for the pest to transfer to a host is considered to be likely with a low uncertainty.

In most cases, both wood in the rough and plants for planting arrive all year round, and these commodities are usually stored outdoors. Therefore, taking D. sibiricus flight ability into consideration, the species will generally have no problems reaching hosts.

Conclusions on the probability of entry

In conclusion the probability of entry of D. sibiricus and D. superans, from areas outside of the PRA area to a suitable habitat within the PRA area are considered as unlikely with a medium level of uncertainty.

The overall assessment behind of this conclusion is that the overall probability of entry by human mediated pathways for D. superans and D. sibiricus is considered as unlikely with a medium level of uncertainty. The probability of natural spread as an entry of D. sibiricus to the PRA area is rated as unlikely with medium uncertainty, while the rating of the probability of natural spread as an entry of D. superans to the PRA-area is considered as very unlikely with low uncertainty.

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3.2 Probability of establishment

Climatic suitability

Rating of climate suitability: Moderately likely

Rating of uncertainty: High

Möykkynen and Pukkala (2014) studied the climate suitability in Europe for D. sibiricus, and they concluded that the climate in central and northern Europe is favourable for establishment. The basis for this analysis was a CLIMEX model originally parameterised by Flament et al. (2017). However, in the latter study, the authors stated that they based the parameter fitting partly on the map “Siberian moth distribution and areas of injuries”, drawn by Rozhkov (1963), except for the mapped western distribution limit. The latter fact seems to be a key assumption with respect to the results of Flament et al. (2017) for the projected distribution for D. sibiricus in regard to the risk of establishment in the PRA area of Norway. It should also be noted that, while the "Rozhkov distribution" focused on areas of injuries, Flament et al. (2017) were more focused on the potential geographical distribution of the organism. The CLIMEX model does not take into account the effect of snow cover. In the case of a species having a strategy of overwintering on the ground, or below ground, the CLIMEX model will have important shortcomings with respect to predicting the actual climate conditions that a ground dwelling, or below ground dwelling species, experience in areas with regular snow cover during winter. Therefore, the Panel has the opinion that the CLIMEX model by Flament et al. (2017) is not able to predict winter survival for D. sibiricus outside is current distribution. Baranchikov et al. (2010) also assessed the potential distribution of D. sibiricus by applying a bioclimatic model (unspecified), and they concluded that the potential for distribution is more constrained than the Flament et al. (2017) study suggested. Milder winter conditions in European Russia than in Siberia may be a limiting factor, as successful overwintering of larvae requires continuous continental-type winters. A large part of Siberia was found to be climatically suitable by Baranchikov et al. (2010) , and the potential distribution closely matches the existing distribution of the pest there. However, for both of these studies the supporting information on presence/absence data is very sparse. Baranchikov et al. (2006) questioned the theory that the distribution of D. sibiricus to the

VKM Report 2018:08 38 west of the Ural Mountains is due to mild winters. The current distribution areas of D. sibiricus have more continental climate, with higher summer temperatures, lower winter temperatures (Figures 6 and 7) and less precipitation (Figure 8) than the PRA-area (Kharuk and Antamoshkina, 2017). Even when looking to the east of Russia, where D. sibiricus is said to be present all the way to the pacific coast, e.g. the coastal city of Vladivostok, the climate is still dominated by cold dry winters and warm summers with low perciptation. Dendrolimus sibiricus outbreaks are associated with high summer temperatures (Figure 6) and low precipitation, (Figure 8) i.e. drought. This is similar to the climate requirements of the European species D. pini (Haynes et al., 2014). Generally, drought stress has been shown to lower the quantity of defensive compounds in the host trees, which make the trees more susceptible to attack (Netherer et al., 2015). In proximity to the oceans, trees experience a more humid climate with less extreme temperature fluctuations, i.e. there is less drought than in continental climates with milder winters. In addition, successful overwintering of D. sibiricus larvae requires continuous winters of a continental type with no autumn thaws, as they are fatal for the larvae (Baranchikov 2009). Therefore, stable sub- zero winter temperatures are probably important for the D. sibiricus larvae (Figure 7).

Figure 6. A map of Russia, Finland, Sweden and Norway showing continentally (monthly maximum temperature minus monthly minimum temperature (°C *10)).

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Figure 7. The minimum temperatures (°C) of January, the coldest month (30 year normal), are generally lower, where Dendrolimus sibiricus is present, than in the PRA-area.

Figure 8. Precipitation during the driest month of the year (August) shows that the total precipitation (millimetres), is lower East of the 60th meridian, and that precipitation is much higher in parts of the PRA-area.

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Natural enemies

Telenomus tetratomus is an important egg parasitoid, which regulates the population densities of several insect species in Russia under non-outbreak conditions (EPPO, 2005). This species is also present in Norway, where it attacks D. pini eggs (Adolfsson, 1984). There are large numbers of parasites attacking D. sibiricus and D. superans in Russia (EPPO, 2005), and some of these may also be present in Norway. In Scandinavia, there are several other species of parasitoids on D. pini (Adolfsson, 1984), some of which may also attack D. sibiricus.

Conclusion of the probability of establishment

Rating of probability of establishment: Unlikely

Rating of uncertainty: Medium

The PRA-area has two potential hosts, Picea abies and Pinus sylvestris, both of which are widely distributed within the area. However, these species are considered as intermediate and poor hosts, respectively (see chapter 2.1.3). In addition, most of the PRA-area has a suboptimal environmental suitability (chapter 3.2.1), with winter temperatures that are not sufficiently cold and with too much precipitation in the summer to allow establishment. The potential of the pests to adapt to new environments is unknown. However, the pest’s life cycle is dynamic, which may be beneficial for adaption to new and adverse conditions.

Dendrolimus sibiricus has never been intercepted outside its main area of distribution, and in Russia there is no, or very slow spread westwards. In addition, there are currently no imports of commodities that would support entry to the PRA-area.

3.3 Probability of spread after establishment

Rating of probability of spread: Likely Rating of uncertainty: High

The exact flight capacities of D. sibiricus and D. superans are unknown, but their behaviour probably depend on the density of suitable host trees, where the species will seek out the nearest suitable host. However, lappet moths are strong flyers, and D. sibiricus is reported to fly up to 100 km per year (EPPO, 2005 and references therein). This flight behaviour is not

VKM Report 2018:08 41 unlikely, since other tree killing moths e.g. the Spruce budworm (Choristoneura fumiferana), are known to mass migrate up to 200 km per year (Boulanger et al., 2017).

Wind direction and wind strength will strongly affect the spread of the moths. In addition, the movement of the commodities: Plants for planting (chapter 3.1.1.4), Wood products (chapter 3.1.1.5) and Foliage or branches (chapter 3.1.1.6), may further aid long-distance spread after establishment.

3.4 Endangered area within the PRA area

The part of the PRA area, where ecological factors may be favourable for establishment, would be the areas with the coldest continuous winters, and the warmest and driest summers. This would probably be the counties furthest from the moderating effects of the Atlantic Ocean, e.g. the counties of Akershus, Hedmark, Oppland, and possibly inner parts of Finnmark.

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3.5 Assessment of impact

Dendrolimus sibiricus and D. superans are considered the most important defoliators and the most destructive pests of conifers in their natural habitat in Russia. In the period from 1994– 1996, D. sibiricus damaged 700.000 hectares of forest in the Krasnoyarsk krai (Zhirin et al., 2016), and between 1954 and 1957 D. sibiricus killed over 1.5 million hectares of pine near the Ket and Chulym rivers (Kharuk et al., 2016). During a period of 25 years, between 1932 and 1957, D. sibiricus damaged 7 million hectares of forest and killed 50% of the trees in West Siberia and Chita Oblast (Baranchikov and Montgomery, 2014; EPPO, 2005). Furthermore, in China, D. sibiricus is considered a major defoliator of the Dahurian larch, Larix gmelinii (EPPO, 2005). For D. superans the pattern of damage is similar. During the period from 1959 to 1964, D. superans caused severe damage to approximately 15.000 hectares of larch-pine forests on the Sakhalin island, Russia (EPPO, 2005). More recently (1986 to 1989), D superans caused the death of 1.800 hectares of forest in Russia(EPPO, 2005).

Continuous defoliation by D. siiricus and D. superans may cause death of forests over large areas, either directly or by leaving forests prone to subsequent attacks by other forest pests, such as woodborers e.g. Scolytidae spp., Cerambycidae spp. (EPPO, 2005). In addition, outbreaks may make the forests more predisposed to forest fires (EPPO, 2005).

Furthermore, the reestablishment of forests after an outbreak is complicated (EPPO, 2005), consequently the attack may lead to major changes in the environment and biodiversity.

In bioassay experiments with D. sibiricus and D. superans, the two Norwegian hosts Picea abies and Pinus sylvestris were described as intermediate and poor hosts, respectively (Kirichenko et al., 2011). However, it is unknown how severe the impact would be under Norwegian climatic conditions, which are regarded as suboptimal. Severe damage caused by outbreaks of D. sibiricus and D. superans in Norway would probably require several years of drought stressed host trees, similar to the circumstances observed during the latest outbreaks of D. pini in Elverum and Løten, Hedmark County, Norway in 1812-1816 and in 1902-1904. However, interactions between D. sibiricus and D. pini could possibly result in more severe outbreaks than those caused by D. pini alone.

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3.6 Conclusion of the impact

The panel concludes that it is unlikely that the pests will have an impact in the foreseeable future within the PRA area. Therefore, the panel concludes that there will be no economic impact from an introduction of the pests. However, this is an assessment with a high uncertainty.

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4 Identification and evaluation of risk reduction options

4.1 Risk reduction options to prevent entry and establishment

Existing phytosanitary requirements, as stated in the commodity-specific phytosanitary measures “PM 8/2 (2) Coniferae” (EPPO, 2014), are regarded as highly applicable for Norway to reduce the risk of introduction of D. sibiricus and D. superans.

The option “Pest-free area for D. sibiricus and D. superans” is problematic, since the true distribution of the species is uncertain in the European part of Russia (west of the 60 ). However, ISPM NO 4. “Requirements for the establishment of pest free areas” could be implemented.

EPPO (2005) recommended that to prevent the introduction of D. sibiricus and D. superans through international movement of commodities, plants for planting and cut branches of host plants from the infested areas should be free from soil. Alternatively, such commodities could originate in a pest free area, be produced in protected houses, fumigated or imported during the winter. Wood should be debarked or heat-treated, originate in a pest free area or be imported during the winter, and isolated bark should be treated to destroy contaminating insects.

Any import of Larix spp., Abies spp., Pinus spp. and Picea spp., genera which the pest is strongly associated with, from areas in Russia where the pests are present, may result in a high probability of entry of D. sibiricus and D. superans in Norway, since egg clusters, larvae and imago may be present on branches and on the stems of the trees. Dendrolimus superans prefers forests older than 50 years of age (EPPO, 2005). However, the panel cannot exclude that the two Dendrolimus species may occur also on younger trees, such as plants for planting.

In the regulations of 1 December 2000 no. 1333 relating to plants and measures against pests (Ministry of Agriculture and Food, 2017) four specific special provisions concerning import to Norway are described.

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§ 16 Import prohibitions, Annex 3, no. 1.1 and 1.2

It is forbidden to import into Norway Coniferales of plants, wood with bark and chips of wood with bark, isolated bark and wood waste of coniferales from Non-European countries and Portugal and all chips of Coniferales from Canada, China, Japan, Korea, Mexico, Portugal, Taiwan and the USA.

§ 17 Conditions of import, Annex 4A, no. 1.1, 1.3 and 5

Official statement that plants and wood of Coniferales originating from specific countries meet the requirement in the annex.

§ 18 Packaging, Annex 4A, no. 1.2

Wood packaging material is covered by specific requirements (in accordance with ISPM 15) for the import of certain plants and other regulated articles. cf. § 17 and Annex 4A.

§ 19 Consignments requiring phytosanitary certification, Annex 5A

Consignments containing plants and other regulated articles (wood) mentioned in Annex 5A shall on import be accompanied by a phytosanitary certificate for export in original or a phytosanitary certificate for re-export in original.

The EU Council Directive 2000/29 describe the following risk reduction measures:

Plants, plant products and other objects the introduction of which shall be prohibited in all member states:

- Isolated bark of conifers = Non-European countries

- Wood in the form of chips, particles, wood waste or scrap and obtained in whole or part from Acer saccharum, Castanea, Platanus, Populus, Quercus originating in non-European countries, and conifers (Coniferales) originating in non-European countries other than Canada, China, Japan, Korea, Taiwan and the USA.

- Plants of conifers (Coniferales) other than fruit and seeds, over 3 m in height, originating in non-European countries.

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4.2 Management options to prevent further spread

4.3 Regulation of Dendrolimus sibiricus and D. superans

The import into Norway from Russia of commodities, that are potential hosts for D. sibiricus and D. superans, has declined during the last 20 years. There has been no import of these commodities during the last five years.

There was significant import of the commodities «Coniferous wood in the rough», «Wood for pulping of spruce and other Coniferous species», «Coniferous saw wood», «Wood for pulping of pine» and «Wood for pulping of other» from Russia. The import of these commodities peaked around the turn of the century and has since ceased. There is an ongoing, but very limited import of “Living plant of unknown species” from China. There was also a very limited import of «Coniferous sawn wood» from Japan in 1992.

Future import will depend on demand for these commodities by Norwegian industries, construction companies and for other purposes.

Both D. sibiricus and D. superans were added to the «EPPO A2 Action List» in 2002, and they are on the current «EPPO A2 List of pests recommended for regulation as quarantine pests» (EPPO, 2017).

Dendroliums sibiricus and D. superans are not regulated in Norway.

Establishment of demarcated zones

Following an outbreak, demarcated zones (infected zone and buffer area) should be established as soon as possible. The Forestry Commission of the United Kingdom recommends the establishment of regulated zones of at least 10 km radius around infested trees (Poulsom, 2016).

Pesticide application

It will be extremely difficult to limit an outbreak of D. sibiricus by pesticide application in Norwegian forests. The control of D. sibiricus in Russia includes the use of both chemical and bacterial products, which are applied by aircrafts and helicopters or by ground based

VKM Report 2018:08 47 spraying. In addition to chemical insecticides, bacterial insecticides containing Bacillus thurigenienesis var. kurstaki have been used to control D. sibiricus in Russia.

Imported host plants for planting and cut branches from the infested area should be free from soil

EPPO (2005) recommended that, to prevent the introduction of both D. sibiricus and D. superans, plants for planting and cut branches imported from infested areas should be free from soil.

Burn infested material

Burning of infested material is suggested as a Pest management procedure by the Forestry Commission, UK (Poulsom, 2016).

Adhesive tape

Adhesive tape has been used to trap Dendrolimus larvae and prevent their upward movement on the trunks of trees (Poulsom, 2016).

4.4 Evaluation of effectiveness and feasibility of risk reduction measures

4.5 Regulation of Dendrolimus sibiricus and D. superans

Regulation of D. sibiricus and D. superans to limit import to pest free areas will reduce the risk for entry of these pests. However, the distribution of the two Dendrolimus spp. is not well known.

A regulation stating that the import of plants for planting and cut branches of host plants should be free from soil, will reduce the risk for introduction of the pests.

Demarcated zones

A prohibition should be imposed on the movement of untreated host material with bark out of the demarcated zone. This applies to wood, branches and other coniferous plant materials and soil that have the potential to be a vector for D. sibiricus and D. superans.

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Prohibition of movement out of the demarcated zones of infested commodities will reduce the risk for spread of D. sibiricus and D. superans.

Pesticide application

The Russian experience is that the application of chemical and bacterial products from the air and on the ground have only limited effects, because of the tremendous amounts of larvae attacking susceptible forest trees during an outbreak of D. sibiricus or D. superans.

There are currently no pesticides approved for insect control in forestry in Norway. With restrictions, similar to the current regulations on chemical weed control in Norwegian forestry, the effect of an application of pesticides on an outbreak of D. sibiricus or D. superans would be very limited.

The regulations for chemical control of vegetation in Norwegian forests states that herbicide application should only be used when it is clearly more effective than mechanical methods, and at the same time the herbicide does not conflict with landscape qualities and recreational values. Vegetation that is on average more than 2 meters high should not be sprayed (Levende skog, 2006).

Pesticide application will have only very limited effect on an outbreak of D. sibiricus or D. superans.

Burning of infested material

Burning of infested material will reduce the risk for spread of D. sibiricus and D. superans if all infested material is burnt. However, burning must comply with environmental protection regulations.

Adhesive tape on trees

A band of adhesive tape around tree trunks prevents the upward movement of insects. This is a relevant control method of D. sibiricus and D. superans on individual trees in parks and gardens. This method is not feasible on a large scale in forestry.

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4.6 Conclusion on the risk reduction measures to prevent entry and establishment

The probability of risk reduction measures to prevent entry and establishment are for both situations considered as unlikely. However, with a high level of uncertainty.

Regulations to stop import of host plant materials, that may harbour D. sibericus and D. superans, will reduce the risk for entry of the pests. However, the distribution of the two Dendrolimus spp. is not well known.

A regulation stating that the import of plants for planting and cut branches of host plants should be free from soil, will reduce the risk for entry of the pests.

Measures such as demarcated zones, pesticide application, regulation of imports, burning of infested materials and adhesive tape on susceptible trees are unlikely to prevent introduction of the pests.

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5 Uncertainties

In the following tables (Table 5 and 6) presented in this chapter, all the uncertainties that have been identified in the different steps of the current opinion are presented.

Table 5. List of Probability and uncertainties for pathways.

Pathway Probability Uncertainty Natural spread of D. Unlikely Medium sibiricus Natural spread of D. Unlikely Low superans Living trees Unlikely Medium Coniferous wood in the Unlikely Medium rough Foliage, branches and other Unlikely High parts of plants Probability of the pest Very Likely High being associated with the pathway Probability of survival Moderately likely High during transport or storage Probability of the pest Unlikely Medium surviving existing pest management procedures Probability of transfer to a Likely Low suitable host Conclusion of the Unlikely Medium probability of entry

Table 6. List of Probability and uncertainties for establishment and spread.

Establishment and Spread Probability Uncertainty Conclusion of the Unlikely Medium probability of establishment Probability of spread after Likely High establishment

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6 Conclusions (with answers to the terms of reference)

Natural spread of D. sibiricus westwards is absent or very slow. There are three main reasons why D. sibiricus and D. superans are unlikely to spread to the PRA-area in the foreseeable future;

There is currently no trade of relevant commodities to facilitate entry into the PRA-area.

The PRA-area and neighbouring countries lack the main hosts of D. sibiricus and S. superans.

There are indications that D. sibiricus prefers a more continental climate than the climate in the PRA-area.

These three factors and the lack of documentation of the alleged westward spread of D. sibiricus suggest that this species will not spread to the PRA-area in the foreseeable future. However, the trade in plants for planting and wood commodities is highly dynamic in space and time, and the risks presented here are based on historical data. Therefore, they do not necessarily reflect the future. However, it is forbidden to import into Norway Coniferales of plants, wood with bark and chips of wood with bark, isolated bark and wood waste of Coniferales from Non-European countries and Portugal are prohibited according to “Regulations of 1 December 2000 no. 1333 relating to plants and measures against pests” (Ministry of Agriculture and Food, 2017).

1. Summarize current knowledge about the taxonomy of D. sibiricus and D. superans and closely allied lappet moths as background for identifying their current distribution areas.

Dendrolimus sibiricus and D. superans should be considered as two separate species (Kononov et al., 2016; Mikkola and Stahls, 2008). Historically, many researchers have considered D. superans to be a single species with two subspecies; D. superans sibiricus Tschetverikov and D. superans albolineatus Butler (Kononov et al., 2016). However,

VKM Report 2018:08 52 according to EPPO (2005) the common international opinion has been that they are two separate species. Genetic analysis by Kononov et al. (2016) has not identified D. superans in mainland Russia, so all references to Dendrolimus superans albolineatus in mainland Russia should be regarded as D. sibiricus.

The Dendrolimus species that occur in Europe and contiguous Russia are according to Mikkola and Stahls (2008) and Kononov et al. (2016):

Lepidoptera (Order) Lasiocampidae (Family) a. Dendrolimus Germar, 1812 (Genus) i. D. pini (Species) ii. D. sibiricus (Species) iii. D. superans (Species)

2. Summarize current knowledge of spread of the species and their host plants, including natural spread. Is there a risk that D. sibiricus can spread naturally from Russia to Norway?

Dendrolimus sibiricus is not expected to spread naturally from its current western distribution limit in Russia (Chuvash Republic, Mari El Republic and Kirov Oblast, Figure 1) to Norway within the foreseeable future. It is not possible to state, with absolute certainty, that the species is not moving westwards based on the current data. However, historical observations indicate that its westward spread is very slow or non-existent. Dendrolimus sibiricus has probably been present west of the 60th meridian since the late 19th century or early 20th century without expanding westwards (Mikkola and Stahls, 2008 and references therein). A few individuals were reportedly pheromone-trapped close to Moscow in 2001, but this observation is rejected by Baranchikov et al. (2006) on the basis of possible misidentification of D. pini as D. sibiricus. In addition, according to Baranchikov et al. (2010) , the distribution of D. sibiricus is limited by the distribution of its preferred host species, Abies sibirica, Pinus sibirica and Larix sibirica (Figure 1), and suboptimal climate conditions in European Russia.

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3. List countries where the status of the pests should be considered as present.

Dendrolimus sibiricus should be considered as present in: Russia, Kazakhstan, Mongolia and China. The previously stated presence in the Democratic People’s Republic of Korea and the Republic of Korea is not supported by Kononov et al. (2016).

Dendrolimus superans should be considered as present in Japan, China, and in Primorsky krai and on the Sakhalin Island, Russia (Kononov et al., 2016).

4. Identify possible pathways for introduction of the two species into Norway.

The two main pathways of concern for D. sibiricus are: (I) Living trees (plants for planting) and (II) wood commodities of conifer wood.

(I) Historically, the import of plants for planting is the pathway of most concern for the introduction of non-native forest insects, because transport of non- native living trees may also carry the non-native forest insects associated with that tree species at origin. All imports of living conifer host trees from the area where D. sibiricus is present could, therefore, lead to a potential introduction into the PRA-area, because the pest spends part of its life cycle on the host trees. There is currently no import of living conifer trees from Russia, and there has not been any import in the past 20 years (see chapter 3.1.3.1). Furthermore, it is forbidden to import into Norway Coniferales of plants, wood with bark and chips of wood with bark, isolated bark and wood waste of Coniferales from Non-European countries and Portugal are prohibited according to “Regulations of 1 December 2000 no. 1333 relating to plants and measures against pests” (Ministry of Agriculture and Food, 2017). However, as global trade increases and trade patterns change rapidly, attention to the origin of plants for planting should be closely monitored, and coupled with the distribution of D. sibiricus and D. superans.

(II) Conifer wood commodities, i.e. round wood and pulpwood, which are not sawn longitudinally, carrying its naturally rounded surface and containing bark, originating from areas where D. sibiricus or D. superans occurs.

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Females of D. sibiricus will lay their eggs on the bark of tree trunks, and thus eggs can be transported between countries. To avoid this, bark needs to be removed from conifer wood commodities originating from areas where D. sibiricus is present.

5. Assess the probability of the pests entering Norway from countries listed in (3) through the pathways listed in (4.).

(I) There is currently no import to Norway of plants for planting from countries where D. sibiricus and D superans are present. In addition, the statistics currently available only provide limited information according to the harmonised custom system. Assessing the probability of D. sibiricus or D. superans entering Norway would require species-specific import statistics of the hosts. However, because the probability of the pests entering Norway is directly related to the propagule pressure (the number of individuals or host plants arriving over time), reduced import rate will reduce the probability of arrival, i.e. no imports equals zero probability.

(II) There is currently no import of conifer wood commodities. However, as global trade increases and trade patterns change rapidly, attention to the origin of plants for planting should be closely monitored, and coupled with the distribution of D. sibiricus and D. superans.

6. Estimate the potential of establishment and further spread of the species in the Norwegian environment if they are introduced, also regarding climatic changes in the future.

The potential for establishment of D. sibiricus are considered as unlikely, with medium uncertainty. The potential of establishment for D. superans are considered as very unlikely with low uncertainty.

The larvae of D. sibiricus probably require continuous, continental winters (Baranchikov et al., 2010), possibly a subarctic climate. Both establishment and further spread will be negatively affected by the Norwegian climate, with winter temperatures that are too high and periods with thawing, as well as too much precipitation during summer. In Norway, the average temperature has increased every decade during the past 115 years, and the

VKM Report 2018:08 55 temperature is expected to increase further, with the highest temperature increase during the winter months, according to both IPPC scenarios RCP8.5 and RCP4.5 (Norsk klimaservicesenter, 2015). In addition, the yearly precipitation has also increased in the period 1900-2014, and the precipitation is expected to increase further (Norsk klimaservicesenter, 2015), which would make future climates even less suitable for D. sibiricus.

The main host plants of D. sibiricus are not present in Norway. Picea abies and Pinus sylvestris are potential hosts in Norway, but they are considered intermediate and poor hosts, respectively.

7. Assess the potential consequences (environmental, economic and social effects) if they are introduced and established in Norway.

We would like you to look at these effects in two scenarios:

a) No regulations for these insects (no measures taken).

b) The insects are regulated as quarantine pests with certain specific requirements.

The panel consider that the answers to terms of reference 7a & b can be identical, as the assessment has not found evidence to suggest that D. sibiricus qualifies as a quarantine pest.

With no measures taken it is assessed that no significant impact is expected on Norwegian forest production and ecosystems. The reason for this assessment is that the Dendroliums species are not expected to cause mass attacks under Norwegian climatic conditions and host availability.

Without any regulations it is possible that the Dendrolimus species would enter the PRA area from time to time. In such a situation the NFSA should be prepared for the case that the pest would cause attention, and the Authority could react by presenting the information given in this opinion.

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Today, it is forbidden to import into Norway Coniferales of plants, wood with bark and chips of wood with bark, isolated bark and wood waste of Coniferales from Non-European countries and Portugal are prohibited according to “Regulations of 1 December 2000 no. 1333 relating to plants and measures against pests” (Ministry of Agriculture and Food, 2017). Furthermore, D. sibiricus is also included in the EU Plant Health Legislation by EU Directive 2000/29 Annex I/AI, requiring a phytosanitary certificate issued by Russia, ensuring that plants and plant products are inspected and free from D. sibiricus (Council Directive 2000/29/EC, 2000 ).

The larvae of D. sibiricus and D. superans feed on the needles of their conifer hosts. Because the insects have overlapping generations, and a life cycle that can last for four years, successive defoliation can kill the host trees. In bioassay experiments with D. sibiricus and D. superans, the two Norwegian hosts Picea abies and Pinus sylvestris were described as intermediate and poor hosts, respectively (Kirichenko et al., 2011). However, it is unknown how severe the impact would be under Norwegian climatic conditions, which are regarded as suboptimal. Severe damage caused by outbreaks of D. sibiricus and D. superans in Norway would probably require several years of drought stressed host trees, similar to the circumstances observed during the latest outbreaks of D. pini in Elverum and Løten, Hedmark County, Norway during 1812-1816 and in 1902-1904. However, interactions between D. sibiricus and D. pini could possibly result in more severe outbreaks than those caused by D. pini alone.

8. Identify relevant risk reduction measures and evaluate their effectiveness and feasibility. For wood packing material, also consider if ISPM 15 is effective enough to prevent the introduction of the pests.

The following risk reduction measures have been identified by the Panel: Import from pest free area, requirement of debarked, heat-treated, treated with ionizing radiation or fumigated wooden materials (EPPO Standard PM 10/6, PM10/8 and PM 10/7 respectively). Plants should be free from soil (EPPO Standard PM 3/54), harvested and imported only in the period between 1st October and 31st March. This measures also applies to plants grown under protected conditions.

Among the risk reduction measures identified, debarking of wood is assessed as the most relevant measure because it is both efficient and technically feasible. The problem with

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pest free area as a measure is that the true distribution of Dendrolimus spp. is not known. With exception from the combination of pest free area and harvesting in the period between 1st October and 31st March, the remaining risk reduction measures identified are generally assessed to be effective, but more demanding with respect to technical implementation.

Effectiveness of the risk reducing measures, described in the EPPO Standards 8/2 (2) Coniferae, under genus-specific requirements for Abies, Picea, Pinus, Larix and Tsuga for the commodities: Plants for planting (except seeds), cut branches, non-squared wood and wood originating in countries where D. sibiricus or D. superans occur, are regarded as applicable for Norway.

EPPO Standards 8/2 for conifer wood applies for imports of all conifer wood originating outside Europe, but does not apply for European Russia i.e. west of the 60th meridian.

ISPM 15 deals with debarked wood packaging material and is not regarded as relevant for Dendrolimus, and, therefore, considered to be effective enough to prevent the introduction of the pests.

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7 Data gaps

In this chapter (Table 7), insufficient knowledge and/or data related to the topic covered in the risk assessment are described. All data gaps described were uncovered during the risk assessment process.

Table 7. Knowledge and/or data uncovered in the current risk assessment and consequences if the knowledge and data would be provided.

Data gaps Consequences if data gaps are filled (for VKM, the assigner, and/or the society) Wide statistical categories: It is Phytosanitary certificates contain impossible to separate relevant information on plant products or other commodity categories to species level regulated articles and specified through the data from statistics Norway. phytosanitary import requirements.

Access to Plant Health Certificates with species level information and the origin of the plants would allow assessing the probability and uncertainty more accurately.

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Data gaps Consequences if data gaps are filled (for VKM, the assigner, and/or the society) Insufficient knowledge of biological Research is needed, or needs to be information of environmental stress made available in English, on the factors, such as cold period, heath period, species capacity to survive long-term or dependency of snow cover for survival. short-term exposure to low temperature at specific developmental stages and how this is affected by snow cover, i.e overwintering. Outbreaks of D. sibiricus has been analysed and quantified by remote sensing (Kharuk et al., 2004). However, the role of snow cover in the life cycle of D. sibiricus are not presented. By Remote sensing it should be relatively easy to analyse the correspondence of permanent snow cover during winter and the outbreak areas.

Also, statements on the negative effect of precipitation need to be backed up by experiments.

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Appendices

Appendix I

List of publications and communications used to compile Figure 1.

Name of federal subjects in Reported as present Reported as not present or Russia disputed Moscow Gninenko and Orlinskii (2002) Mikkola and Stahls (2008)

(Gninenko Y.U and Kryukov Baranchikov et al. (2006) V.Y.U, 2007) Sverdlovsk Kulinich personal communication (2017) Tuva Gninenko and Orlinskii (2002) Buryat Gninenko and Orlinskii (2002)

Mikkola and Stahls (2008) Tyumen Orlinski (2006) Tomsk Gninenko and Orlinskii (2002) Amur Gninenko and Orlinskii (2002) Sakha (Yakutia) Gninenko and Orlinskii (2002) Khabarovsk Gninenko and Orlinskii (2002) Krasnoyarsk Gninenko and Orlinskii (2002)

N. and Beskorovainaia (2008)

Valendik et al. (2006)

Galkin (1993) Chita Gninenko and Orlinskii (2002) Perm Kulinich personal communication (2017)

Mikkola and Stahls (2008) Udmurtiya Kulinich personal communication (2017)

Mikkola and Stahls (2008) Irkutsk Gninenko and Orlinskii (2002)

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Name of federal subjects in Reported as present Reported as not present or Russia disputed Primorye Mikkola and Stahls (2008) Kirov Kulinich personal communication (2017)

Gninenko and Orlinskii (2002)

Kononov et al. (2016) Marii-El Kulinich personal Baranchikov et al. (2006) communication (2017) Mikkola and Stahls (2008) (Gninenko Y.U and Kryukov V.Y.U, 2007) Chuvash Kulinich personal communication (2017) Chelyabinsk Kulinich personal communication (2017)

Mikkola and Stahls (2008) Khakass Kononov et al. (2016) Sakhalin Kononov et al. (2016) Novosibirsk Gninenko and Orlinskii (2002)

Kharuk et al., (2004) Altay Gninenko and Orlinskii (2002) Bashkortostan Gninenko and Orlinskii (2002)

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Appendix II

Ratings and descriptors are based on Appendix 2 in VKMs Risk Assessment of cockspur grass (Echinochloa crus-galli).

Table A1-1; Rating of probability of entry.

Rating Descriptors

Very unlikely The likelihood of entry would be very low because the pest:  is not, or is only very rarely, associated with the pathway at the origin  no import volume,  may not survive during transport or storage  cannot survive the current pest management procedures existing in the risk assessment area  may not transfer to a suitable habitat in the risk assessment area

Unlikely The likelihood of entry would be low because the pest:  is rarely associated with the pathway at the origin,  very low import volume,  survives at a very low rate during transport or storage,  is strongly limited by the current pest management procedures existing in the risk assessment area,  has considerable limitations for transfer to a suitable habitat/crop in the risk assessment area.

Moderately The likelihood of entry would be moderate because the pest: likely  is frequently associated with the pathway at the origin,  moderate import volume,  survives at a low rate during transport or storage,  is affected by the current pest management procedures existing in the risk assessment area,  has some limitations for transfer to a suitable habitat/crop in the risk assessment area.

Likely The likelihood of entry would be high because the pest:

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 is regularly associated with the pathway at the origin,  high import volume,  mostly survives during transport or storage;  is partially affected by the current pest management procedures existing in the risk assessment area,  has very few limitations for transfer to a suitable habitat/crop in the risk assessment area.

Very The likelihood of entry would be very high because the pest: likely  is usually associated with the pathway at the origin,  very high import volume,  survives during transport or storage;  is not affected by the current pest management procedures existing in the risk assessment area,  has no limitations for transfer to a suitable habitat/crop in the risk assessment area.

Table A1-2: Rating of the probability of establishment Rating Descriptors

Very unlikely The likelihood of establishment would be very low because:  of the absence or very limited availability of suitable habitat/crop;  the unsuitable environmental conditions;  and the occurrence of other considerable obstacles preventing establishment.

Unlikely The likelihood of establishment would be low because:  of the limited availability of suitable habitat/crop;  the unsuitable environmental conditions over the majority of the risk assessment area;  the occurrence of other obstacles preventing establishment

Moderately The likelihood of establishment would be moderate because: likely  suitable habitats/crops are abundant in a few areas of the risk assessment area;

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 environmental conditions are suitable in a few areas of the risk assessment area;  no obstacles to establishment occur

Likely The likelihood of establishment would be high because:

 suitable habitats/crops are widely distributed in some areas of the risk assessment area;  environmental conditions are suitable in some areas of the risk assessment area;  no obstacles to establishment occur.  Alternatively, the pest has already established in some areas of the risk assessment area

Very likely The likelihood of establishment would be very high because:  hosts plants are widely distributed;  environmental conditions are suitable over the majority of the risk assessment area;  no obstacles to establishment occur.  Alternatively, the pest has already established in the risk assessment area

Table A1-3: Ratings used for describing the level of uncertainty Rating Descriptors

Low No or little information is missing or no or few data are missing, incomplete, inconsistent or conflicting. No subjective judgement is introduced. No unpublished data are used.

Medium Some information is missing or some data are missing, incomplete, inconsistent or conflicting. Subjective judgement is introduced with supporting evidence. Unpublished data are sometimes used.

High Most information is missing or most data are missing, incomplete, inconsistent or conflicting. Subjective judgement may be introduced without supporting evidence. Unpublished data are frequently used.

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